Hey!

A score of 450 will fetch you a rank between 82216-89872. You can check it here

It is quite difficult to accurately say about the chances of getting a college as cut off varies every year depending on various factors, but based on previous year data, you have a decent chance of getting a college in Maharashtra in EWS category. Following are the colleges you may get based on the second round result of Maharashtra 2019-

IIMSR Jalna

Vedanta Medical College, Palghar

Mgm dental college new Mumbai

Dy patil dental college Pune

To know more about Maharashtra cut off you can check here https://medicine.careers360.com/articles/neet-cutoff-maharashtra

For admission in Karnataka, you need to register through KEA as a out state student. You will only be eligible for the private seats in Karnataka. For MBBS, at your rank its quite difficult to get a seat there as MBBS closed around 17839 last year. You will get a BDS seat there as BDS closed around 252870 last year.

You can check Karnataka cut off here https://medicine.careers360.com/articles/neet-cutoff-karnataka

To get a list of colleges you have a chance of getting MBBS/BDS seat, you can use the NEET College Predictor here